There is presently provided numerous devices for displaying data which is based upon radar, infrared scanning, laser verification, etc. These may utilize cathode-ray tubes (CRT) or other display means which would provide image reproduction that can be monitored by a viewer.
In many applications, i.e., military, medical, environmental, etc., it is desirable, if not imperative, that a real time display of the image be provided which allows a human operator to effectively detect and recognize targets or items.
At low spatial frequencies, the chromatic response of the operator exceeds the achromatic response so that certain images which are indistinguishable in a monochrome display, would be descernable in a color display. For example, often it is necessary to distinguish a temperature variation of 0.1.degree. K. within a 300.degree. background which would be impossible in a monochrome arrangement.
Accordingly, it is advantageous to utilize pseudo or false color to discriminate multi-sensor data. While pseudo colors have been utilized in non-real time applications i.e., Landsat and ERT satellites mapping an original color or infrared image described by perhaps primary colors i.e., Red, Green, and infrared, it does not provide a real time display of linear functions of spectral signatures of the image.
While the use of digital scan conversion of such data for CRT displays would be advantageous, the use of conventional long persistent PPI or CRTs in conventional operational circuitry in displaying such data as pseudo-colors is limited. Present high resolution scan or image conversion and color display utilize costly cosmetic colors for manual modes of operation and usually make color cues as to possible targets questionable and often distracting.
In addition, since present infrared sensors, particularly that of the trichroic, multi-discriminant processing type, scan at high speeds, refresh electronics and memory is necessary to a read out at a T.V. frame rate to enable the operation to detect targets and to continually update the data displayed. Conventional color CRTs and video amplifier arrangements are ineffective in providing such displays and color code assignments in such arrangements would be diluted, decreasing their effectiveness.